When the agency’s newest rover mission searches for fossilized microscopic life on the Red Planet, how will scientists know if they found it?
The NASA Perseverance Mars 2020 rover will be the agency’s new mission to land on the Red Planet. Along with characterizing the planet’s geology and climate and paving the way for human exploration beyond the moon, the rover focuses on astrobiology or the study of life throughout the universe. Perseverance is tasked with looking for revealing signs that microbial life may have lived on Mars billions of years ago. It will collect core rock samples in metal tubes, and future missions would return these samples to Earth for further study.
“To quote Carl Sagan,” said Gentry Lee, chief engineer of the Department of Planetary Sciences at NASA’s Jet Propulsion Laboratory. “If we see a hedgehog looking in the room, we would know that there is current life and certainly ancient on Mars, but based on our past experiences, such an event is extremely unlikely. Extraordinary claims require extraordinary evidence, and the discovery that life existed elsewhere in the universe would certainly be extraordinary. ”
Scientists on the Mars 2020 mission believe that Jezero Crater, the landing site of Perseverance, could host such evidence. I know that 3.5 billion years ago, Jezero was the site of a large lake with its own river delta. They believe that although the water may have long since disappeared, somewhere in the 28-mile-wide (45-kilometer-wide) crater or perhaps along its 2,000-meter-high (610-meter-high) rim, the biosignatures (evidence that life has once existed there) could wait.
“We expect the best places to look for biosignatures to be in the bed of Lake Jezero or in the sediments on the shore, which could be encrusted with carbonate minerals, which are particularly good at preserving certain types of fossilized life on Earth.” said Ken Williford, deputy project scientist for the Mars 2020 Perseverance rover mission at JPL. “But as we look for evidence of ancient microbes in an ancient alien world, it’s important to keep an open mind.”
NASA’s fifth rover to the fourth planet from the Sun carries a new suite of scientific tools to build on the findings of NASA’s Curiosity rover, which discovered that parts of Mars could have supported microbial life billions of years ago.
Biosignature hunting
Any biosignature hunt will include a suite of rover cameras, especially the Mastcam-Z (located on the rover’s mast), which can magnify to inspect scientifically interesting targets. The mission’s scientific team can commission the SuperCam tool of Perseverance – also on the mast – to shoot with a laser at a promising target, generating a small cloud of plasma that can be analyzed to help determine its chemical composition. If this data is interesting enough, the team could order the robot arm of the rover to come in for a closer look.
To do this, Perseverance will rely on one of the two tools on the turret at the end of his arm. PIXL, the Planetary Instrument for X-ray Lithochemistry) will use its small or powerful X-ray beam to look for potential chemical traces of past life. The SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument has its own laser and can detect concentrations of organic and mineral molecules that have formed in aqueous media. Together, SHERLOC and PIXL will provide high-resolution maps of the elements, minerals and molecules in Martian rocks and sediments, allowing astrobiologists to evaluate their composition and determine the most promising cores to collect.
A lasting hope for the scientific team is to find a surface feature that could not be attributed to anything other than ancient microbial life. Such a feature could be something like a stromatolite. On Earth, stromatolites are undulating, rocky mounds, formed long ago by microbial life along the ancient coast and in other environments where metabolic energy and water were abundant. Such a visible feature would be difficult to approach even in geological processes.
“Yes, there are certain shapes that form in rocks where it is extremely difficult to imagine a lifeless environment that could cause that shape to form,” Williford said. “That being said, there are chemical or geological mechanisms that can cause layered dome-shaped rocks, as we usually think of as a stromatolite.”
Enter the sample cache system sample. The collection of engines, planetary gearboxes and sensors with the size of the steam trunk is among the most complex, capable and cleanest mechanisms ever sent into space. With this, the scientific team will collect the most interesting samples they can find, store them in test tubes and then submit them so that future missions can collect the sample tubes and fly them back to Earth for analysis. .
“The tools needed to definitively prove microbial life when it existed on Mars are too large and complex to be brought to Mars,” said Bobby Braun, JPL’s Mars Sample Return program manager. “That’s why NASA is working with the European Space Agency on a multi-mission effort, called Mars Sample Return, to take the samples that Perseverance collects and bring them back to Earth for study in laboratories around the globe. ”
And when that happens, samples from Mars’ Perseverance rover can tell us that, at some point, billions of years ago, life existed elsewhere in the universe. But they can also indicate the opposite. And what then?
“We have strong evidence that Jezero Crater once had the ingredients for life. Even if after the analysis of the returned sample we conclude that the lake was uninhabited, we will have learned something important about reaching life in the cosmos “, said Williford. “Whether or not Mars has ever been a living planet, it is essential to understand how rocky planets like ours form and evolve. Why did our planet remain hospitable as Mars became a wasteland? “
Perseverance may not be the last word on whether the red planet has ever contained life, but the data it collects and the discoveries it makes will play a key role whenever this result is reached.
Mankind has focused on Mars since Galileo became the first man to see it through a telescope in 1609. Did it ever have a life? The answer may be waiting for us somewhere in Jezero Crater. NASA’s Perseverance Rover will begin the process tomorrow.
More about the mission
A key goal of the Perseverance on Mars mission is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and hide the rock and Martian rule.
Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for further analysis.
The Mars 2020 mission is part of a broader program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. With the task of returning astronauts to the moon by 2024, NASA will establish a sustained human presence on and around the moon by 2028 through NASA’s Artemis lunar exploration plans.
JPL, which is managed for NASA by Caltech in Pasadena, California, has built and manages the operations of the Perseverance rover.
For more about perseverance:
mars.nasa.gov/mars2020/
nasa.gov/perseverance
For more information on NASA missions to Mars, visit:
https://www.nasa.gov/mars
News Media Contacts
DC Agle
Jet Propulsion Laboratory, Pasadena, California.
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Alana Johnson / Gray Tombstone
NASA Headquarters, Washington
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